Phosphor Distribution in LED Wavelength Conversion for Chromaticity Control
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Solution Overview
Problem
Semiconductor light emitting devices with fixed phosphor proportions exhibit variations in light wavelength, leading to chromaticity variations due to inconsistencies in the thickness of light emitting sections and degradation of resins used in the manufacturing process.
Innovation Solution
A semiconductor light emitting device design that includes a wavelength conversion section with a distribution of phosphor amounts based on the wavelength of light emitted from the light emitting sections, using a resin resistant to degradation, and a wall section to prevent mixing of different phosphor concentrations, ensuring consistent chromaticity across the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed proportion of phosphor is blended into the resin, then the manufacturing process is simple, but chromaticity variation increases due to wavelength variation in light emitting elements
Solution Approach 1:
The patent applies local quality by varying the phosphor concentration in different regions of the wavelength conversion section. Specifically, the phosphor concentration is adjusted according to the wavelength characteristics of light emitting elements at each position, with higher phosphor concentration for elements emitting shorter wavelengths and lower concentration for elements emitting longer wavelengths. This spatial variation in phosphor concentration compensates for wavelength variations and maintains consistent chromaticity across the entire device.
2Manufacturing precision
If the phosphor concentration is increased to compensate for wavelength variation, then chromaticity consistency improves, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the phosphor concentration parameter across different regions of the wavelength conversion section. The phosphor concentration is adjusted as a continuous parameter based on the wavelength characteristics of the light emitting elements, creating a gradient distribution rather than uniform concentration. This parameter variation enables chromaticity control while using a single resin material system.
3Quantity of substance
If regular resin is used in the wavelength conversion section, then the manufacturing cost is low, but the resin degrades over time affecting device lifespan
Solution Approach 1:
The patent applies composite materials by formulating a specialized resin composition for the wavelength conversion section that incorporates degradation-resistant components. The resin includes specific additives and modifiers that enhance UV resistance and thermal stability, creating a composite material system that maintains mechanical and optical properties over extended periods under LED operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses chromaticity variations by adjusting phosphor amounts according to light wavelength, maintaining consistent color perception and extending the lifespan of the device by using resistant resins, thereby improving manufacturing efficiency and product quality.
Implementation Method 1
a wavelength conversion section (8) having a distribution of amount of the phosphor (52) based on a distribution of wavelength of light emitted from the light emitting section (2)
Implementation Method 2
degradation of resins used in the manufacturing process
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a light emitting section and a wavelength conversion section. The light emitting section is configured to emit light. The wavelength conversion section is provided on one major surface side of the light emitting section. The wavelength conversion section contains a phosphor. The wavelength conversion section has a distribution of amount of the phosphor based on a distribution of wavelength of the light emitted from the light emitting section.